MELBOURNE, Fla. – Hours after his opponents Mitt Romney and Paul Ryan did a Sunday morning TV show blitz, President Barack Obama criticized them for not offering more specifics on how they would keep revenue stable while not raising taxes on the wealthy.

“Governor Romney and his allies tell us that we can somehow lower our deficit by spending trillions on new tax breaks for the wealthy. Listen, you’ve got to do the math because when my opponents were asked about it today, they couldn’t. It was like two plus one equals five,” Obama told a crowd of more than 3,000 in a gymnasium at the Florida Institute of Technology here.

When asked during an interview on NBC’s “Meet the Press” what tax loopholes he would eliminate, Romney got no more specific than telling host David Gregory, “high income taxpayers are going to have fewer deductions and exemptions.”

On ABC News’ “This Week,” Ryan said Romney and he would consult with Congress before deciding which loopholes to cut. “We want to do this with the consent of the elected representatives of the people and figure out what loopholes should stay or go,” he said.

Ever mindful of his local audience, Obama also focused heavily on Medicare, an important issue to the 17.6 percent of Florida’s population over age 65 – more than four percentage points over the national average.

He cited a new study by Harvard Professor David Cutler that found seniors who qualify for Medicare beginning in 2023 would see higher premiums over the course of their retirement under the Romney/Ryan plan, which would give seniors the option of getting a voucher to help pay for private insurance in addition to the traditional government-run program.

Cutler, one of the Obama campaign’s chief health care advisers in 2008, conducted the study on behalf of the Center for American Progress Action Fund, a liberal advocacy organization.

“Basically your profits would decline by the thousands so their profits could rise by the billions,” Obama said of the study’s conclusion.

The Romney campaign responded with a statement from spokesman Ryan Williams calling the study "discredited."

"President Obama’s latest false attacks are a sign of desperation. Only one candidate in this race has robbed today’s Medicare of $716 billion to pay for Obamacare – Barack Obama. He has done nothing to reform Medicare for the long haul and prevent it from going bankrupt, and on his watch family health care premiums have increased by nearly $2,500," the statement read in part.

In Melbourne, the president also mentioned another issue important to voters on this slice of Florida’s coast, whose economy is buoyed in part by the space industry.

“Here on the Space Coast, we started a new era of American exploration that is creating more jobs right here,” Obama said, noting the Curiosity rover that landed on Mars last month.

He warned that Republicans would stifle the research and development that his administration has encouraged.

“This is where we’ve got a choice. We could, as the House Republican budget proposes, cut back on research and technology or we can continue to be at the cutting edge because that’s what we’ve always been about,” he said.

The president is now on his way to West Palm Beach for the fourth and final stop on his two-day Sunshine State campaign swing, after which he’ll return to the White House – hopefully, he said this afternoon, in time to catch Sunday Night Football.

“We intend to be finished to get home in time for kickoff,” he told the crowd in Melbourne.